basement subpanel question


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Old 05-31-06, 01:22 PM
K
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basement subpanel question

I'm planning on finishing a 1400 sq ft basement and am considering installing a subpanel. The reason for the sub is to make wiring the basement simpler, since they would all need to be fed out through the garage, into the garage roof and down to the main panel.

The main service is 200A Challenger, and has the following breakers:
50/50 - 1 (hot tub)
40/40 - 1 ( range)
30/30 - 2 ( ac/dryer)
20 - 5
15 - 8

There are 5 empty slots currently.

The basement plans include:
lighting (recessed, unsure about the wattage, maybe 75w or 100w),
home theatre,
home office ( about 8 computers, 4 monitrs, 1 printer)
a bathroom, bedroom and a side room

So here are my questions:

How big of a sub panel?
What type and size of wire? Can this be run through pvc conduit in the garage space down the wall? What size conduit ?

Thanks
 
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Old 05-31-06, 01:47 PM
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Originally Posted by Ken66
I'm planning on finishing a 1400 sq ft basement and am considering installing a subpanel. The reason for the sub is to make wiring the basement simpler, since they would all need to be fed out through the garage, into the garage roof and down to the main panel.
A good application for a subpanel.

The main service is 200A Challenger, and has the following breakers: hot tub, range, ac/dryer, 20A 5, 15A 8

There are 5 empty slots currently.
The breaker sizes alone don't tell the whole story without adding up the actual loads they supply. However with a 200A service, I'll give you a 95% chance of not being close to overload. If you want to perform the actual calculation, look up the "demand load calculation".

How big of a sub panel?
Common sizes for subpanels are 60A and 100A, although just about anything in between is possible. If you are very concerned about cost, a 60A will be cheaper. If you want more flexibility for future expansion, go with a 100A subpanel. The loads you listed will be just fine on a 60A, but if you ever plan to use big power tools, a kiln, etc in the basement the 100A panel might be a better choice.

What type and size of wire?
Depends on the distance and subpanel size. A 60A subpanel can be fed with #6/3 copper MN-B (Romex) or THHN in conduit. There are also aluminum cables which can help reduce cost. You have to pick a panel size before picking the feeders.

Can this be run through pvc conduit in the garage space down the wall? What size conduit?
Yes, it is also possible that you can use a cable without conduit. If you go with conduit, don't install anything less than 1-1/4".
 
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Old 05-31-06, 02:20 PM
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A rough estimate on the distance is about 40-45 feet (5 feet up, 16 feet over, 10feet down, 5 feet over and 5 feet down.

Also, I'd like to leave a little room for expansion, so I think the local pizza box hardware store has an 80amp sub. That is fairly inexpensive.

I'll search and do some more research on the load. At this point, its just to check/verify that this project is doable, before I start getting contractors involved.

thanks
 
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Old 06-01-06, 12:14 PM
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Originally Posted by Ken66
Can this be run through pvc conduit in the garage space down the wall? What size conduit ?

Thanks
Ken
PVC, which is properly called Rigid Nonmetallic Conduit, must be protected by at least 1/2" sheet rock if it is run inside a dwelling. That is done to limit the "smoke contributed" when PVC is exposed to a fire. PVC conduit may not penetrate the fire resistive wall assembly that separates the garage space from the rest of your home. I'd strongly suggest that you run either Electro Metallic Tubing (EMT) or Type SE cable style R which is commonly called SER. EMT, which is commonly called thin wall conduit is made of mild steel and can be installed almost as easily as PVC. SER cable has a flame-retardant covering. #1 American Wire Gage Aluminum SER with three insulated conductors and one bare conductor within an overall cable jacket is perfectly suitable for the feeder to a one hundred ampere panel. If you decide to go with a smaller panel now then run the EMT in the 1&1/4" size so you can change to a larger size feeder later. If it were mine to do I would go straight to the one hundred ampere size so that I'd have the capacity and the breaker slots for future use.
 
 

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